mineral

Labradorite (or Plagioclase Feldspar Pebble)

(Ca,Na)(Al,Si)4O8

Hardness: 6.0-6.5 on Mohs scale. Color: Grayish-green to dark gray, translucency with potential labradorescence (schiller effect). Luster: Vitreous to sub-vitreous. Cleavage: Perfect in two directions intersecting at nearly 90 degrees.

Hardness: 6
Luster: Vitreous to sub-vitreous

Identified July 22, 2026More mineral →

Explore Labradorite (or Plagioclase Feldspar Pebble) in the encyclopedia →

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Physical properties

Formation & geological history

Forms in intermediate to mafic igneous rocks such as basalt, gabbro, and anorthosite. High-grade metamorphic conditions can also preserve feldspar-rich pebble formations via river and ocean erosion.

Uses & applications

Used primarily as a decorative gemstone, cabochons, carved ornaments, lapidary art, and for mineral collection.

Geological facts

Labradorite exhibits optical iridescence known as labradorescence, caused by internal fractures or lamellar intergrowths that refract light into vivid blue, green, yellow, or orange flashes.

Field identification & locations

Look for internal fractures, smooth water-worn texture on beach pebbles, and subtle blue/green flash reflections when held under light at specific angles. Commonly found along beaches in Canada, Madagascar, and Russia.

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